1. Field of the Invention
The present invention relates generally to connectors, and more particularly to a plug-side connector and a jack-side connector used where data are transmitted at high rate.
2. Description of the Related Art
With recent developments in personal computers and their networks, systems are required to transmit a large amount of video data in particular. In order to transmit a large amount of video data, it is necessary to perform data transmission at high rates greater than or equal to, for example, 1 gigabit per second (Gbps).
At high data transmission rates greater than or equal to 1 Gbps, signals become shorter in wavelength, so that particularly in a part of a transmission path where a plug-side connector is connected to a jack-side connector, electromagnetic waves are likely to leak out from the connectors. Therefore, it is necessary to take measures against EMI (Electromagnetic Interference).
Meanwhile, differential transmission, which has the merit of being less susceptible to noise than conventional transmission methods, has been adopted as a data transmission method. According to differential transmission, a “+” signal to be transmitted and a “−” signal equal in magnitude and opposite in direction to the “+” signal are simultaneously transmitted using a pair of electric wires for each data item.
FIGS. 1 and 2 are diagrams showing a conventional plug-side connector 20 and a conventional jack-side connector 50. In FIGS. 1 and 2, X1-X2 indicates the width directions of the plug-side connector 20 and the jack-side connector 50, Z1-Z2 indicates the height directions of the plug-side connector 20 and the jack-side connector 50, Y1 indicates a direction in which the plug-side connector 20 is inserted into the jack-side connector 50, and Y2 indicates a direction in which the plug-side connector 20 is extracted from the jack-side connector 50. These directions are the same for the other drawings.
Here, the plug-side connector 20 is held by a hand of an operator and connected to the jack-side connector 50, which is fixed to an apparatus so as to be exposed on a side of the apparatus. The plug-side connector 20 and the jack-side connector 50 form a connector unit 10, to which the above-described differential transmission system is applied.
The plug-side connector 20 includes a zinc die-cast housing 23 and a contact assembly 30 incorporated therein. The housing 23 includes an upper cover 21 and a lower cover 22. The plug-side connector 20 is provided at an end of a cable 40. The contact assembly 30 has contact members 32 and 33 arranged and attached to a block formed of an insulator (an insulating block) 31.
The housing 23 has a frame part 25 provided at an end thereof. Further, a latch claw 27 is provided on each of the X1 and X2 sides of the housing 23.
The jack-side connector 50 has contact members 52 and 53 arranged and attached to a block formed of an insulator (an insulating block) 51. The block 51 has a front-side (Y2-side) projecting part thereof covered with an electromagnetic shield cover member 56 having a cap-like shape. A gasket 58 is attached so as to surround the front-side part of the block 51. A metallic lock part 54 projects in the Y2 direction from the front side of the block 51 at each of the X1 and X2 ends thereof.
The electromagnetic shield cover member 56 is formed by pressing carbon steel into a cap-like shape. The electromagnetic shield cover member 56 has convex parts 57 arranged on each of the upper and lower sides thereof at such a predetermined pitch as to enable formation of an electromagnetic shield. The gasket 58 is formed by pressing a metal plate of a copper alloy, and includes multiple arranged leaf spring pieces 59.
The jack-side connector 50 is mounted on an end of a printed circuit board 70 with leg parts 54a of the metallic lock parts 54 being fitted into and soldered to corresponding holes of the printed circuit board 70 and ends of the contact members 52 and 53 being soldered to corresponding pads on the printed circuit board 70.
The printed circuit board 70 is, for example, incorporated in a server unit 80 so that a front-side projecting part 50a of the jack-side connector 50 projects outside the server unit 80 in the Y2 direction through an opening 82 of a metallic panel (IO panel) 81. The electromagnetic shield member 56 of the jack-side connector 50 is electrically connected to the panel 81 of the server unit 80 through the gasket 58 so as to be at frame ground potential. The multiple leaf spring pieces 59 are in contact with the panel 81 so as to form an electromagnetic shield in the gap between the opening 82 of the panel 81 and the jack-side connector 50.
The frame part 25 of the plug-side connector 20 is fitted around the projecting part 50a of the jack-side connector 50, so that the contact members 32 and 33 are connected to the contact members 52 and 53, respectively, and the latch claws 27 engage the corresponding metallic lock parts 54. As a result, the plug-side connector 20 is connected to the jack-side connector 50.
The frame part 25 surrounds the projecting part 50a, and the housing 23 of the plug-side connector 20 is electrically connected to the electromagnetic shield cover member 56 so as to be at frame ground potential. The interior side of the frame part 25 comes into contact with the convex parts 57 of the electromagnetic shield cover member 56. The contact points are arranged at a predetermined pitch, thereby forming an electromagnetic shield where the plug-side connector 20 is connected to the jack-side connector 50.
Reference may be made to Japanese Laid-Open Patent Application No. 2004-111249 for the above-described technique.
The cable 40 may be unnecessarily pulled during operations such as system maintenance. In this case, the plug-side connector 20 is prevented from being disconnected from the jack-side connector 50 because the latch claws 27 engage the corresponding metallic lock parts 54, but the plug-side connector 20 may be moved in the Z1-Z2 or X1-X2 directions. If the plug-side connector 20 is moved, some of the convex parts 57 are separated from the interior side of the frame part 25. This causes the convex parts 57 and the frame part 25 to be in contact with each other at a pitch several times the above-described predetermined pitch, so that the electromagnetic shield may be broken to cause leakage of electromagnetic noise from this broken part.
Further, the electromagnetic shield may also be broken to cause leakage of electromagnetic noise when an operator moves or pries the plug-side connector 20 connected to the jack-side connector 50 in order to perform operations such as checking the connection.